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TD-LTE系統(tǒng)中探測參考信號(hào)的DSP實(shí)現(xiàn)
來源:電子技術(shù)應(yīng)用2011年第12期
劉文文,李校林,李小文
(重慶郵電大學(xué) 重慶市移動(dòng)通信技術(shù)重點(diǎn)實(shí)驗(yàn)室,重慶400065)
摘要: 探測參考信號(hào)在TD-LTE系統(tǒng)中用于上行信道質(zhì)量的測量。介紹了探測參考信號(hào)SRS生成涉及的各個(gè)公式,給出了程序?qū)崿F(xiàn)的設(shè)計(jì)流程。并采用TI公司TMS320C64系列的DSP、使用C和匯編語言進(jìn)行軟件編程生成SRS信號(hào)。最后對(duì)最難運(yùn)算且最耗時(shí)的除法和指數(shù)運(yùn)算的實(shí)現(xiàn)進(jìn)行了巧妙的設(shè)計(jì)。該實(shí)現(xiàn)方法已應(yīng)用于LTE-TDD無線綜合測試儀表的開發(fā)中。
關(guān)鍵詞: LTE SRS ZC序列
中圖分類號(hào): TN929.5
文獻(xiàn)標(biāo)識(shí)碼: A
文章編號(hào): 0258-7998(2011)12-0053-03
DSP realization of sounding reference signal in TD-LTE system
Liu Wenwen,Li Xiaolin,Li Xiaowen
Chongqing Key Laboratory of Mobile Communications, Chongqing University of Posts and Telecommunications,Chongqing 400065,China
Abstract: Sounding reference signal is used for the uplink channel quality measurements in TD-LTE system. At beginning, this paper provides the various formulas that generating the SRS, and then gives the design flow chart for programming realization. After that, use TI TMS320C6455 DSP to generate SRS by software programming, definitely speaking, by using C and Assembly ianguage. Finally, this paper specifically describe the realization of division and exponentiation because it’s the hardest and most time-consuming operations in the DSP implementation. The method written in this paper has been applied to LTE-TDD wireless integrated test instrument development.
Key words : LTE;SRS;ZC Sequence


    為了應(yīng)對(duì)移動(dòng)通信與寬帶無線接入技術(shù)融合的趨勢,提高數(shù)據(jù)傳輸速率,3GPP啟動(dòng)了通用移動(dòng)通信系統(tǒng)技術(shù)的長期演進(jìn)LTE(Long Term Evolution)項(xiàng)目。LTE系統(tǒng)將最大系統(tǒng)帶寬從5 MHz擴(kuò)展到20 MHz,選用了OFDM和MIMO等關(guān)鍵技術(shù),下行鏈路采用頻譜效率較高的OFDMA方式,上行鏈路采用SC-FDMA技術(shù),以降低發(fā)射終端的峰均功率比,減小終端的體積和成本。
    上行參考信號(hào)SRS(Sounding Reference Signal),在LTE系統(tǒng)中被用于上行信道質(zhì)量的測量。由終端(UE)發(fā)送、網(wǎng)絡(luò)端(基站)接收,網(wǎng)絡(luò)端用來支持頻率選擇性調(diào)度、功率控制和定時(shí)提前等功能,具有十分重要的作用。SRS的生成比較繁瑣,本文基于3GPP最新版本,針對(duì)DSP中匯編難以實(shí)現(xiàn)的除法和指數(shù)計(jì)算提出了一種新的實(shí)現(xiàn)方案,降低了實(shí)現(xiàn)的難度,同時(shí)也保持了較高的運(yùn)算精度。
1 SRS序列生成的各個(gè)模塊
1.1 組序號(hào)u和組內(nèi)序列號(hào)v的產(chǎn)生

 





 

    在LTE系統(tǒng)中,SRS主要用于信道質(zhì)量估計(jì),實(shí)現(xiàn)上行信道的頻率選擇性調(diào)度。在DSP實(shí)現(xiàn)中,除法和指數(shù)運(yùn)算是很難進(jìn)行的,本文針對(duì)SRS的算法,結(jié)合具體的DSP匯編指令,巧妙地設(shè)計(jì)了除法和混合查表法的指數(shù)實(shí)現(xiàn)方案,并且成功地生成了SRS。經(jīng)過驗(yàn)證可以得到混合查表法的精度高于普通的查表法,而實(shí)現(xiàn)的復(fù)雜度增加不大。
參考文獻(xiàn)
[1] 3GPP.TS 36.211 v9.0.0 evolved universal terrestrial radio access(E-UTRA) physical channels and modulation(release 9)[S].s.l.:3GPP,2009.
[2] Wei Xie,Li Xiaowen.Study on the frequency offset correction of TDD-LTE synchronization signal based on ZC sequence[J].Electronic Test,2009,3(5).
[3] Texas Instruments corporation.TMS320C6455 technical reference.2005.
[4] Texas Instruments Corporation.TMS320C64x/C64x+ DSP CPU and instruction set reference guide.2008.
[5] 王信松,張節(jié)松.復(fù)變函數(shù)[M].合肥:中國科學(xué)技術(shù)大學(xué)出版社,2011.
[6] 邱建琪,林瑞光,孫依軍.基于DSP的SPWM混合查表實(shí)時(shí)計(jì)算法[J].微特電機(jī),2001(1).

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